U.S. Pat. No. 5,005,808 is directed to the end attachment of an air spring flexible member to respective connecting parts. FIG. 4 shows all essential details. The attachment part includes a slot for attaching a sleeve rolling-lobe flexible member end section. This slot has a base surface which can be provided with peripherally-extending grooves 24. The flanks of the slot are partially curved and partially conically inclined at different angles α and β. The clamping takes place via the compression of the flexible member over the entire elevation of the clamp ring. The elastomeric material of the flexible member is practically incompressible. For this reason, the clamping over the entire clamp ring elevation hR has the consequence that, to a considerable extent, elastomeric material is squeezed out at both sides of the clamp ring in the longitudinal direction of the flexible member. In view of the fact that the flexible member is provided with a reinforcement, which is expandable slightly compared to the rubber, the problem is present that the considerable longitudinal displacement of the elastomeric material can lead to unwanted excessive longitudinal stresses within the flexible member and therefore to a possible separation of the elastomeric material from the reinforcement which can expand only slightly.
In order to avoid internal longitudinal stresses of the above kind in the clamping region of the flexible member, DE 41 42 561 A1 suggests that the end section of the flexible member not be pressed over the entire elevation of the clamp ring and instead only at an upper and/or lower “constriction” in the region of at least one of the flanks of the attachment slot. FIG. 4 shows the “constriction” 21 at the lower slot flank 22 while the flexible member is practically not compressed over the entire clamping elevation of the clamp ring. Because of the rectangular slot cross section in the construction shown in FIG. 4, the insertion of the clamp ring, which is to be mounted, is not easily possible.
An easier assembly possibility is to be expected by the variation shown in FIG. 1. Here too, the basic idea of the flexible member attachment is that no compression is present over the elevation of the clamping length and therefore no greater material displacement is present in the longitudinal direction of the flexible member; instead, the basic idea of the flexible member attachment is rather that the clamping takes place only at short “constrictions” 21 in the region of the slot flanks. The rounded clamp geometry includes no gripping capacity. Accordingly, with respect to the construction shown in FIG. 1, the desired pull-out strength does not appear to be satisfied especially to the extent as is required in commercial vehicles.